1. Field of the Invention
The present invention relates to a technique for generating a processed image depending on an input image.
2. Description of the Related Art
An image forming apparatus such as a printer, a copier, or a multi-function device forms a processed image depending on an input image on a sheet. To be specific, such an image forming apparatus executes a print job given thereto to form an image onto a sheet. The input image is inputted in the form of image data from a host requesting the image forming apparatus to carry out printing. Alternatively, the input image is given to the image forming apparatus in the form of being recorded on a document sheet.
When a print job is executed, information of an input image is partly missing in a printed processed image, i.e., a print image. Such information is missing typically in the case where an image forming apparatus is a monochrome image forming apparatus and an input image is a color image. In such a case, color information of the input image is missing.
There has been proposed a conventional technique for reproducing missing information. According to such a conventional technique, in monochrome facsimile transmission, a processed image to be sent is given a two-dimensional barcode where color information, which is expected to be missing, is expanded to the processed image. At a receiving end, the processed image received is converted into a color image based on the two-dimensional barcode given to the processed image. The resultant is then printed (Japanese Laid-open Patent Publication No. 2006-345049).
There has been proposed a conventional technique for preventing color information from missing. According to such a conventional technique, when an image having a color code symbol is printed in monochrome, an image and a monochrome code symbol having code information represented by a color code symbol are synthesized. The resultant synthesized image is then printed (Japanese Laid-open Patent Publication No. 2014-024193).
In the meantime, a variety of services using Augmented Reality (AR) technology has recently been provided. According to the AR technology, when a printed matter having an AR marker thereon is photographed by, for example, a smartphone, a content corresponding to the AR marker is displayed on an image of the photographed printed matter. This enables a user to feel as if the actual space were augmented. Effects similar thereto can be observed by using wearable computers (glasses-type).
According to the conventional technique described in Japanese Laid-open Patent Publication No. 2006-345049, information expected to be missing is represented by an added image such as a two-dimensional barcode. Therefore, an amount of information reproducible is limited to a predetermined value of, at most, approximately 3000 bytes. To be specific, when an amount of missing information is small, all of the missing information can be reproduced. Unfortunately, however, when an amount of missing information is greater than the predetermined value, only a part of the missing information can be reproduced.
The case where an amount of missing information is small includes, for example, a case where an input image is a text image and all the characters are depicted in a color other than black, e.g., in red. In such a case, information indicating that a character color is “red” is represented in the form of a two-dimensional barcode. Thereby, based on a processed image to which a two-dimensional barcode is added and is printed in black, a text image having red characters can be printed or displayed. In a case where some character strings of a text image are red, and the others are blue, information indicating that the m-th line through the n-th line are red and the x-th line is blue can be represented in the form of a two-dimensional barcode. This enables the original text image to be reproduced.
In contrast, the case where an amount of missing information is large includes, for example, a case where an input image has a full-color picture. In such a case, the full-color picture has a large amount of color information represented by a product of the number of pixels and a color of each pixel. Therefore, even if the two-dimensional barcode or any other additional images are used, it is impossible to represent the entirety of the missing information. Thus, only a part of the missing information can be reproduced.